ABSTRACT Kidney cancer is one of the ten most common cancers in the US and accounts for over 100,000 deaths each year. Over 80% of kidney cancers are classified as clear cell renal cell carcinoma (ccRCC), and insight as to how this disease develops is scarce. One characteristic of ccRCC is the overexpression of NADH dehydrogenase (ubiquinone) 1 alpha subcomplex, 4-like 2 (NDUFA4L2), which is overexpressed in over 90% of ccRCC patients. Additionally, NDUFA4L2 is necessary for cell proliferation and survival, therefore indicating its importance in the development of ccRCC. However, the function of NDUFA4L2 has yet to be elucidated. Previous studies have shown that NDUFA4L2 plays a role in the switch from mitochondrial oxidative phosphorylation to glycolysis, a metabolic shift that is observed in ccRCC. Additional studies suggested that NDUFA4L2 may be implicated in the inhibition of mitochondrial complex I activity. However, this proposed function has yet to be investigated in ccRCC. Functional studies on NDUFA4L2 in vivo are lacking due to the prenatal lethality of NDUFA4L2 knockout mice. The Gudas lab has generated a TRAnsgenic Cancer of the Kidney (TRACK) murine model in which NDUFA4L2 is overexpressed. Additionally, this novel murine model recapitulates the human ccRCC disease, as demonstrated by genome- wide profiling of the TRACK kidneys. Previous collaborative work between the Gudas lab and the Heller lab showed that mesoscale nanoparticles (MNPs) localize in the mouse kidneys up to 25 times more than they do in other organs. Furthermore, these MNPs localized more in the ?clear? cells, or lipid-filled cells, of the TRACK kidneys relative to normal proximal tubule cells. Consequently, these MNPs present a novel method of delivering drugs, therapeutics, or other investigative tools to the site of disease in the renal carcinogenesis murine model. We therefore aim to utilize this innovative approach to investigate the function of NDUFA4L2 in ccRCC. Through the utilization of the TRACK mouse model and the kidney-targeting MNPs, we will: 1) elucidate the role of NDUFA4L2 on mitochondrial function, and 2) determine the knockdown efficacy of siNDUFA4L2-encapsulating MNPs in TRACK mice. In order to investigate the mitochondrial function of NDUFA4L2, we will analyze mitochondrial function, ATP production, ROS levels, and complex I activity in cultured human ccRCC cells and TRACK mice. MNPs encapsulating siRNA specific for NDUFA4L2 will then be injected into TRACK mice to investigate whether NDUFA4L2 knockdown can be successfully achieved using this novel method. The proposed studies will delineate the functions of NDUFA4L2 in ccRCC and elucidate a possible delivery method of NDUFA4L2 knockdown specific to the kidneys. Findings from this proposal will provide critical insight into the underlying processes of ccRCC and present potential therapeutic strategies.